The author report the cases of three women with aortic regurgitation associated with aneurysmal dilatation of the ascending thoracic aorta. Aortic valve replacement was carried out in the 3 cases, with resection of the aortic aneurysm in 2 cases. Histological examination of the aortic wall in all 3 cases showed non-specific aortitis in the adventitia and media, appearances comparable to those described in Takayasu's disease. The incidence of aortic regurgitation in Takayasu's disease is about 10%. These 3 cases are compared with 30 other cases with histological confirmation in the medical literature, only 9 of which have undergone aortic valve replacement. The mechanism of the aortic regurgitation is analysed: dilatation of the aortic ring, inflammation of the valve cusps, commissural dysjunction or dilatation of the ascending aorta involving the line of commissural insertion. Aortic regurgitation is usually associated with other arterial localisations of the disease, but may also be found alone when the disease seems limited to the ascending aorta. Coronary artery disease, especially ostial, is observed in 30% of patients with this type of aortic regurgitation. Coronary angiography is therefore mandatory before surgery. The arterial involvement may be investigated initially and followed-up by 2 non-invasive investigations = digitalised intravenous angiography (DIVA) and M mode and 2D echocardiography. The two investigations give comparable results with regards to the study of the aorta, but the branches of the aorta and pulmonary arteries can only be investigated by DIVA.(ABSTRACT TRUNCATED AT 250 WORDS)